Who made the best 6GH8A ?
 

Picked up some NOS for my RCA CTC-38, I have GE, RCA and Sylvania, all made in USA, wondering which will last the best.

The GE's would be longest lasting, followed by the Sylvania's. The RCA's are OK, where the circuit isn't too hard on them, like AGC and sync. :scratch2:

Used to buy Zenith branded ones by the gross for 19 cents.
They seemed to work as good as any but I dont know who
made them. Radio Shack ones were junk. people would
replace a few & we always came out & replaced them. When
old they are fussy as to where they work. In other words they
may work in AGC but no 3.58 osc.

73 Zeno:smoke:

I used a lot of Zenith branded tubes, back then. They had a better price on them, than the RCA's and GE's. Don't remember a price like that.
GE and Sylvania made most of the replacement, Zenith tubes.
RadioShack tubes, seemed to be Japanese Raytheon's. :boring:

My CTC-38 was only serviced by an RCA authorized dealer, and had all RCA tubes in it still. When I got it, the picture would come on for about 5 minutes, and then totally lose sync. I swapped the AGC and the Sync tubes, and the picture stays in sync but is a bit less sharp than before I swapped tubes.

I tested all the tubes and the bad one is a little bit weak, and has a white RCA logo versus the red one of the replacement tubes, so it is original to the set. I also replaced one of the 6GH8s in the colour section which had bad heater/cathode leakage with a used good Admiral tube I had laying around.

My plan is to wait for a rainy day, pull the chassis, and replace all the electrolytic capacitors, plus the formerly Sync now AGC 6GH8A and the one in the colour section where I put in the used Admiral tube. Now that I have the Sams for the set (thank you, zeno!) I can see there's a decent list of capacitors needing replacement, but not too many.

This TV actually lives in the living room, and is used as my primary TV for family entertainment - I posted a thread on it in the rectangular tube tv section a while back. It's really got a nice picture, aside from a slight waviness probably due to aged capacitors. Reliability is somewhat important, since it's my main TV set, but on the other hand I don't expect perfection out of a 46 year old TV... I also have a spare junk chassis for it, but no spare yoke or CRT.

Interestingly all of the horizontal tubes - the horizontal output, the damper, the high voltage rectifier, are RCA replacements with a 1970 date code all marked "Japan", I didn't know RCA was sourcing tubes from Japan so early on!

My CTC51K, all the OEM tubes are Japanese, but the 3A3. There was three tubes changed by the original owner. Two 6GH8's and a 11HM7.
Naturally, the 6GH8's were in the color circuit and were GE. The 11HM7, video output was a Sylvania.
After I bought it, I had to repair the vertical circuit. It's a set, I referred to in an earlier thread. :scratch2: